thanks to Jeff Schwartz. Objectify is very good ! thanks to Erick Fleming too.
2010/12/5 Jeff Schwartz <[email protected]> > Odd but I don't see him needing either cursors or 2 indexes to achieve his > required result and it doesn't even need a filter condition. IMO it just > requires a descending ordering with a limit of 1. > > On Sat, Dec 4, 2010 at 11:38 AM, Erick Fleming <[email protected]>wrote: > >> In Java you can use Query cursors to [1] limit your results. As far as >> aggregate functions (like MIN and MAX) you can use [2] indexes to achieve >> the similar result (ie. order by age and get the top result) >> >> [1] >> http://code.google.com/appengine/docs/java/datastore/queriesandindexes.html#Query_Cursors >> <http://code.google.com/appengine/docs/java/datastore/queriesandindexes.html#Query_Cursors> >> [2] >> http://code.google.com/appengine/docs/java/datastore/queriesandindexes.html#Introducing_Indexes >> <http://code.google.com/appengine/docs/java/datastore/queriesandindexes.html#Introducing_Indexes> >> On Sat, Dec 4, 2010 at 10:31 AM, Jeff Schwartz >> <[email protected]>wrote: >> >>> Conceptually they are tables, but not in the same sense as SQL tables. >>> They are more like a hash map and if you think of them in those terms you >>> will be better served. >>> >>> Are you coding in Python or Java. If you are coding in Java then here's >>> an example: >>> >>> query(Some.class).order('age').limit(1).get() >>> >>> >>> On Sat, Dec 4, 2010 at 11:16 AM, Zeynel <[email protected]> wrote: >>> >>>> On Dec 4, 11:08 am, Tim Hoffman <[email protected]> wrote: >>>> > Remember there are no tables. Just kinds representing models. >>>> >>>> I am confused by this statement. When I look at the Development >>>> Console - Datastore Viewer; I see a table named after the model. In my >>>> case, I have a table called User with columns "userEmail", "userName" >>>> and so on. Each row in this table is what the documentation calls an >>>> "instance" of the class. So what is the justification for the >>>> statement that there are no tables? >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Google App Engine" group. >>>> To post to this group, send email to [email protected]. >>>> To unsubscribe from this group, send email to >>>> [email protected]<google-appengine%[email protected]> >>>> . >>>> For more options, visit this group at >>>> http://groups.google.com/group/google-appengine?hl=en. >>>> >>>> >>> >>> >>> -- >>> *Jeff Schwartz* >>> >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "Google App Engine" group. >>> To post to this group, send email to [email protected]. >>> To unsubscribe from this group, send email to >>> [email protected]<google-appengine%[email protected]> >>> . >>> For more options, visit this group at >>> http://groups.google.com/group/google-appengine?hl=en. >>> >> >> >> >> -- >> Erick Fleming >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Google App Engine" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]<google-appengine%[email protected]> >> . >> For more options, visit this group at >> http://groups.google.com/group/google-appengine?hl=en. >> > > > > -- > *Jeff Schwartz* > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-appengine%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
